scholarly journals A miniPCR-Duplex Lateral Flow Dipstick Platform for Rapid and Visual Diagnosis of Lymphatic Filariae Infection

Diagnostics ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1855
Author(s):  
Achinya Phuakrod ◽  
Witsaroot Sripumkhai ◽  
Wutthinan Jeamsaksiri ◽  
Pattaraluck Pattamang ◽  
Sumat Loymek ◽  
...  

Lymphatic filariasis (LF) is a neglected major tropical disease that is a leading cause of permanent and long-term disability worldwide. Significant progress made by the Global Programme to Eliminate Lymphatic Filariasis (GPELF) has led to a substantial decrease in the levels of infection. In this limitation, DNA detection of lymphatic filariae could be useful due to it capable of detecting low level of the parasites. In the present study, we developed a diagnostic assay that combines a miniPCR with a duplex lateral flow dipstick (DLFD). The PCR primers were designed based on the HhaI and SspI repetitive noncoding DNA sequences of Brugia malayi and Wuchereria bancrofti, respectively. The limits of detection and crossreactivity of the assay were evaluated. In addition, blood samples were provided by Thais living in a brugian filariasis endemic area. The miniPCR-DLFD assay exhibited a detection limit of 2 and 4 mf per milliliter (mL) of blood for B. malayi as well as W. bancrofti, respectively, and crossamplification was not observed with 11 other parasites. The result obtained from the present study was in accordance with the thick blood smear staining for the known cases. Thus, a miniPCR-DLFD is an alternative tool for the diagnosis of LF in point-of-collection settings with a modest cost (~USD 5) per sample.

2021 ◽  
Author(s):  
Achinya Phuakrod ◽  
Witsaroot Sripumk ◽  
Wutthinan Jeamsaksiri ◽  
Pattaraluck Pattamang ◽  
Sumart Loymek ◽  
...  

Abstract Background: Lymphatic filariasis is a major neglected tropical disease that is a leading cause of permanent and long-term disability worldwide. Significant progress made by the Global Programme to Eliminate Lymphatic Filariasis (GPELF) has led to a substantial decrease in the levels of infection. Accordingly, access is now needed to a cost-efficient, non-laborious diagnostic assay(s) capable of detecting low levels of microfilariae and without the need for infrastructure and expensive equipment.Methods: We developed a diagnostic assay that combines a miniPCR with a duplex lateral flow dipstick (DLFD) assay. The design of the PCR primers was guided by sequence alignments of the HhaI and SspI genes of Brugia malayi and Wuchereria bancrofti, respectively. The limits of detection, accuracy, and cross-reactivity of the assay were evaluated, after which the assay was deployed to assess infection using blood samples obtained from Myanmar study participants living along the Thailand-Myanmar border, a region in Tak province endemic W. bancrofti. In addition, blood samples were provided by from Thais in Narathiwat province residing in an area endemic for brugian filariasis. We also combined a previously reported semi-automated microfluidic device with the miniPCR-DLFD to facilitate rapid detection and species identification of microfilariae in human blood.Results: The miniPCR-DLFD assay exhibited a detection limit of two microfilariae per mililiter blood sample, and cross-amplification was not observed with from other parasites. For field validation, microfilariae and DNA of W. bancrofti were detected from two (0.6%) and five (1.5%) out of 328 (100%) blood samples, respectively. For the Narathiwat samples, microfilariae and DNA of B. malayi were detected from one (0.46%) and two (0.9%) out of 216 (100%) blood samples, respectively. A rapid and visual of species identification was accurately obtained in all microfilariae entrapped by our previously developed microfluidic device.Conclusion: A miniPCR-DLFD platform alone or coupled with the microfluidic device provided rapid and visual diagnosis of lymphatic filariasis. The microfluidic device, the miniPCR, and the DLFD are all portable. Coupled with a portable microcentrifuge for DNA extraction, this is a promising platform for the diagnosis of lymphatic filariasis in point-of-collection settings with a modest cost (~USD $ 5) per sample.


2013 ◽  
Vol 20 (8) ◽  
pp. 1155-1161 ◽  
Author(s):  
Cathy Steel ◽  
Allison Golden ◽  
Joseph Kubofcik ◽  
Nicole LaRue ◽  
Tala de los Santos ◽  
...  

ABSTRACTThe Global Programme to Eliminate Lymphatic Filariasis has an urgent need for rapid assays to detect ongoing transmission of lymphatic filariasis (LF) following multiple rounds of mass drug administration (MDA). Current WHO guidelines support using the antigen card immunochromatographic test (ICT), which detects active filarial infection but does not detect early exposure to LF. Recent studies found that antibody-based assays better serve this function. In the present study, two tests, a rapid IgG4 enzyme-linked immunosorbent assay (ELISA) and a lateral-flow strip immunoassay, were developed based on the highly sensitive and specificWuchereria bancroftiantigen Wb123. A comparison ofW. bancrofti-infected and -uninfected patients (with or without other helminth infections) demonstrated that both tests had high sensitivities and specificities (93 and 97% [ELISA] and 92 and 96% [strips], respectively). When theW. bancrofti-uninfected group was separated into those with other filarial/helminth infections (i.e., onchocerciasis, loiasis, and strongyloidiasis) and those who were parasite uninfected, the specificities of the assays varied between 91 and 100%. In addition, the geometric mean response by ELISA ofW. bancrofti-infected patients was significantly higher than the response of those withoutW. bancroftiinfection (P< 0.0001). Furthermore, the Wb123 ELISA and the lateral-flow strips had high positive and negative predictive values, giving valuable information on the size of survey population needed to be reasonably certain whether or not transmission is ongoing. These highly sensitive and specific IgG4 tests to theW. bancroftiWb123 protein give every indication that they will serve as useful tools for post-MDA monitoring.


2014 ◽  
Vol 2014 ◽  
pp. 1-4 ◽  
Author(s):  
Catherine Maldjian ◽  
Vineet Khanna ◽  
Bevan Tandon ◽  
Matthew Then ◽  
Mohamed Yassin ◽  
...  

Lymphatic filariasis is the most common cause of acquired lymphedema worldwide (Szuba and Rockson, 1998). It is endemic to tropical and subtropical regions, and its effects are devastating. With over 100 million infected persons, it ranks second only to leprosy as the leading cause of permanent and long-term disability.Wuchereria bancroftiis the etiologic agent in 90% of cases. There is a dearth of published MRI findings with pathologically proven active infections, making this entity even more of a diagnostic dilemma. Imaging may provide the first clue that one is dealing with a parasite and may facilitate proper treatment and containment of this disease. This is the first report of pathologic correlation with MRI findings in the extremity in active filariasis. The magnetic resonance images demonstrate an enhancing, infiltrative, mass-like appearance with partial encasement of vasculature that has not been previously described in filariasis. Low signal strands in T2-hyperintense dilated lymphatic channels are seen and may depict live adult worms. We hypothesize that the low signal strands correspond to the collagen rich acellular cuticle. This, in combination with the surrounding hyperintense T2 signal, corresponding to a dilated lymphatic channel, may provide more specific MRI findings for active nematodal infection, which can prompt early biopsy, pathological correlation, and diagnosis.


2015 ◽  
Author(s):  
Daniel Quang ◽  
Xiaohui Xie

Modeling the properties and functions of DNA sequences is an important, but challenging task in the broad field of genomics. This task is particularly difficult for noncoding DNA, the vast majority of which is still poorly understood in terms of function. A powerful predictive model for the function of noncoding DNA can have enormous benefit for both basic science and translational research because over 98% of the human genome is noncoding and 93% of disease-associated variants lie in these regions. To address this need, we propose DanQ, a novel hybrid convolutional and bi-directional long short-term memory recurrent neural network framework for predicting noncoding function de novo from sequence. In the DanQ model, the convolution layer captures regulatory motifs, while the recurrent layer captures long-term dependencies between the motifs in order to learn a regulatory "grammar" to improve predictions. DanQ improves considerably upon other models across several metrics. For some regulatory markers, DanQ can achieve over a 50% relative improvement in the area under the precision-recall curve metric compared to related models.


2020 ◽  
Vol 13 (Supplement_1) ◽  
pp. S33-S38
Author(s):  
Gilberto Fontes ◽  
Eliana Maria Mauricio da Rocha ◽  
Ronaldo Guilherme Carvalho Scholte ◽  
Rubén Santiago Nicholls

Abstract In South and Central America, lymphatic filariasis (LF) is caused by Wuchereria bancrofti, which is transmitted by Culex quinquefasciatus, the only vector species in this region. Of the seven countries considered endemic for LF in the Americas in the last decade, Costa Rica, Suriname and Trinidad and Tobago were removed from the World Health Organization list in 2011. The remaining countries, Brazil, Dominican Republic, Guyana and Haiti, have achieved important progress in recent years. Brazil was the first country in the Americas to stop mass drug administration (MDA) and to establish post-MDA surveillance. Dominican Republic stopped MDA in all LF-endemic foci: La Ciénaga and Southwest passed the third Transmission Assessment Survey (TAS) and the Eastern focus passed TAS-1 in 2018. Haiti passed the TAS and interrupted transmission in &gt;80% of endemic communes, achieving effective drug coverage. Guyana implemented effective coverage in MDAs in 2017 and 2018 and in 2019 scaled up the treatment for 100% of the geographical region, introducing ivermectin in the MDA in order to achieve LF elimination by the year 2026. The Americas region is on its way to eliminating LF transmission. However, efforts should be made to improve morbidity management to prevent disability of the already affected populations.


Life ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 762
Author(s):  
Yihong He ◽  
Wenxian Chen ◽  
Jindai Fan ◽  
Shuangqi Fan ◽  
Hongxing Ding ◽  
...  

Porcine parvovirus (PPV) infection is the primary cause of SMEDI (stillbirth; mummification; embryonic death; infertility) syndrome, which is a global burden for the swine industry. Thus, it is crucial to establish a rapid and efficient detection method against PPV infection. In the present work, we developed a recombinase-aided amplification (RAA) assay, coupled with a lateral flow dipstick (LFD), to achieve an amplification of PPV DNA at 37 °C within 15 min. The detection limits of PPV RAA-LFD assay were 102 copies/μL recombinant plasmid pMD19-T-VP1, 6.38 × 10−7 ng/μL PPV DNA, and 10−1 TCID50/mL virus, respectively. This method was highly specific for PPV detection with no cross-reactivity for other swine pathogens. In contrast to polymerase chain reaction (PCR), the PPV RAA-LFD assay is more sensitive and cost-saving. Hence, the established PPV RAA-LFD assay provided an alternative for PPV detection, especially in resource-limited regions.


1995 ◽  
Vol 51 (5) ◽  
pp. 5084-5091 ◽  
Author(s):  
S. V. Buldyrev ◽  
A. L. Goldberger ◽  
S. Havlin ◽  
R. N. Mantegna ◽  
M. E. Matsa ◽  
...  

Author(s):  
Allassane F Ouattara ◽  
Catherine M Bjerum ◽  
Méité Aboulaye ◽  
Olivier Kouadio ◽  
Vanga K Marius ◽  
...  

Abstract Background Ivermectin (IVM) plus albendazole (ALB), or IA, is widely used in mass drug administration (MDA) programs that aim to eliminate lymphatic filariasis (LF) in Africa. However, IVM can cause severe adverse events in persons with heavy Loa loa infections that are common in Central Africa. ALB is safe in loiasis, but more information is needed on its efficacy for LF. This study compared the efficacy and safety of three years of semiannual treatment with ALB to annual IA in persons with bancroftian filariasis. Methods Adults with Wuchereria bancrofti microfilaremia (Mf) were randomized to receive either three annual doses of IA (N=52), six semiannual doses of ALB 400mg (N=45), or six semiannual doses of ALB 800mg (N=47). The primary outcome amicrofilaremia at 36 months. Findings IA was more effective for completely clearing Mf than ALB 400mg or ALB 800mg (79%, CI 67-91; vs. 48%, CI 32-66 and 57%, CI 41-73, respectively). Mean % reductions in Mf counts at 36 months relative to baseline tended to be greater after IA (98%, CI 88-100) than after ALB 400mg (88%, CI 78-98) and ALB 800mg (89%, CI 79-99) (P=0.07 and P=0.06, respectively). Adult worm nest numbers (assessed by ultrasound) were reduced in all treatment groups. Treatments were well tolerated. Interpretation Repeated semiannual treatment with ALB is macrofilaricidal for W. bancrofti and leads to sustained reductions in Mf counts. This is a safe and effective regimen that could be used as MDA to eliminate LF in areas ivermectin cannot be used.


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